Gr11 Chem Exam - Unit 1

Dobrenier

Law of triads (groups of 3 with sim properties, middle mass is the average of the other two)

Newlands

Law of octaves (family resemblance)

mendeleev

noticed trends, left open space for missing elements, organized by similar properties + increasing mass

mendeleev periodic law

increasing atomic mass

modern periodic law

increasing atomic #

F1

alkali metals, reactive, soft

F2

Alkaline earth metals, less reactive, more solid than F1

F1, 2, 13-18

representative elements, represent tmain trendss

F17

Halogens, gasses, most unreactive nm’s

F18

noble gasses: unreative

F3-12

transitional metals: multivalent

elements (l) at satp

Hg, Br

bolded elements are …

synthetic elements: man-made

pure covalent bond

diatomic molecules, EN = 0, elecrons completely equally shared

Democritus

atomism: matter is made of tiny building blocks called atoms

dalton

billiard ball model, atomic theory (atoms are indivisible)

thomson

plum pudding model, cathode ray expirement (discovered electrons)

rutherford

nuclear model, cold foil expirement, discovered nucleus (most of atom is empty soace, small dense +ve area inc enter, electrons orbit nucleus randomly)

bohr

planetary model, electrons move on energy levels with diff. capacities, e- can transition form levels by losing/gaining energy

chadwick

neutrons, why dont P+ and N reject eahother in nucleus?

Atomic #

Z, # of protons (nuvlear charge)

mass #

A, (p + n), rounded atomic mass

atomic mas

mass of atom on sclae of C-12 = 12u (unified atomic mass unit)

average atomic mass

weighted avergae of isotoped in naturally occuring elements, Mav = (Mx-1)(%x-1) + (Mx-2)(%x-2)…

isotopic mass

mass of an isotope (Mx-1)

isotopic abundance

(%x-1) percent abundance of isotope in a sample of the element

isotope

variation of # of n in same atom (O-17, oxygen-17)

radioisotopes

unstable isotopes that decay while emitting energy

proton

positively charged subatomic particle in atom (mass = 1u)

neutron

neutrally charged subatomic particle in atom (mass = 1u)

electron

negatively charged ubatomic particle in atom (mass = 0.00055u)

atomic radius

half the distance between the nuclei of two atoms (bonded or not)

decreases down periods, increases down family

ionic radius

Measure of nucleus to outermost shell in ion

cations: increases downs family, decreases along period
anions: increases down family, increases along period

more -ve charge = bigger ionic radius
more +ve charge = smaller ionci raidus

ionization energy

amount of energy required to remove electron from atom in gaseous state

increases down p, decreases down f

electronegativity

atoms ability to attract electrons when bonded

increases down p, decreases down f

Electron affinity

amount of energy released when an atos gains and electron in the gaseous state

increases down p, decreases down f

higher ea = easier pick up of e-
lower ea = harder pick up of e-

isoletric ions

same # of ions, diff atomic number

3 factors affecting periodic trends

nuclear charge, effective nuclear charge, shielding effect

bohr rutherford diagrams

p/n + shells (2, 8, 8)

electron arrangement

p/n) #e- ) #e- ) #e-

electron dot diagram

symbol + dots

atomic notatio

A/Z Symbol, or A Symbol

ionic compounds properties

(s) at SATP
ionic bonds (transfer of electrons)

Crystal Lattice

Brittle + Hard

High melting/boiling point

White

release electrolytes in solution (condictive)

soluble

ionic compounds diagrams

e- dot diagrams

(Be)+2 2(Cl (+ dots))-

stable octet

atoms want to acheive, when outer shell is full of valnece e-

noble gas configuratino

when atoms have stable octet

isoletric atoms

atoms are isoletric with a noble gas when they have a stabe octet (ex: Na and Ne)

Changing oxygen in polyatomic ions for name writing

per = +1, ite = -1, hypo+ite = -2

Changing H in polyatomic ion

+1 H = +1 charge

Iupac = Hydrogem _

Classical = bi_

monovalent vs multivalent

monovalent = one charge

multivalent = multiple ion charges

radical for multivalent ions in ionic compunds

Ferr (Fe)

Cupr (Cu)

Stann (Sn)

Stibn (Sb)

Aur (Au)

Mercur (Hg)

Cobalt (Co)

Plumb (Pb)

molecular compounds properties

soft

(s), (l) or (g) at SATP

dissolve well or not at all

do not conduct electricity

molecular/covalent bonds (sharing of electrons)

form molecules

Diatomic molecules

nm’s that bond with themselves

HOF BR(l) I(s) NCL

types of diagrams for molecular compounds

electron dot diagrams (only dots)

;lewis structure (dots and lines)

structural formula/diagram (only lines)

lone/non-bonding pairs

unbonded electrons in compound

bonding capacity

amount of bonding pairs between both atoms possible

coordinate covalent bond

one atom supplies both electrons for molecular bond

bond types

ionic (EN>=1.7)

polar (1.7>EN>0.4)

non-polar covalent (EN>=0.4)

illustrating polar bonds in diagrams

bond dipole arrow

partial charges

what is the electronegativity for diatomic molecules

0

why and how do ionic bonds happen

atoms want stable octet, metals will give away electrons and non-metals will take them, opposite charges attract, Electronegativity > 1.7

why and how do covalent bonds/polar covalent bonds happen

atoms want stable octets, nm’s do this by sharing electrons. If one atom is more electronegative than the other, the shared electrons will be shared unequally therefore causing a polar bond

why are ionic compounds are conductive

because they release free ions in solutions which are able to conduct electrical currents

explain gold foil expirement

A piece of gold foil was hit with alpha particles, which have a positive charge. Most alpha particles went right through. This showed that the gold atoms were mostly empty space. Some particles had their paths bent at large angles. A few even bounced backward. The only way this would happen was if the atom had a small, heavy region of positive charge inside it.

explain cathode ray expirement

how many SD in average atomic mass calculation

2 (average atomic mass/atomic mass always has 2 sd)